Surface acoustic wave (SAW) devices generally consist of two or more transducers formed from interlocking (interdigitated) comb-like arrays of elements in contact with a piezoelectric material. At high frequencies, these piezoelectric devices are capable of providing a considerable reduction in the size, complexity and power consumption of certain components and subsystems, such as filters and oscillators, used in modern communications and radar systems. By decreasing the widths of the elements and the inter-element spacing in the arrays of elements that form the transducers that generate and/or detect the surface acoustic waves in the piezoelectric material from about 1 micron to about 0.1 micron, the operable frequency range may be increased from about 1 GHz to about 10 GHz.
Presently, the elements of surface acoustic wave devices are made by conventional photolithographic, chemical etching and metallization techniques. Photolithographic techniques are ecnomically and technically capable of commercially producing elements as small as about 1 micron in width. In order to achieve sub-micron widths and thereby decrease size and increase operating frequency, resort must generally be made to pioneering electron beam and X-ray lithographic techniques. At the present time, these pioneering techniques are slower and more expensive, especially in terms of capital equipment costs, than the more conventional photolithographic techniques.
Thus, there is a need for surface acoustic wave devices having near-micron and sub-micron sized component parts and features, i.e., elements and inter-element spacing, and for methods by which those near-micron and sub-micron sized features can be produced reproducibly and inexpensively.